Format conversion of digital video signals, integration of digital video signals into photographic film material and the like, associated signal processing, and motion compensated interpolation of images

Abstract

A system for integrating film material with a digital video signal employs a film scanner to produce a digital video signal from the source film, and a post production system for combining with that signal the input digital video signal. Motion interpolated temporal compensation is employed at stages of frame rate conversion.

What we claim is: 
     
       1. A method of converting an input 60 field/s 2:1 interlace scan format digital video signal to an output 24 frame/s 60 field/s 3232 pulldown format digital video signal, comprising the steps of: forming a first series of 60 frame/s progressive scan format frames from the fields of the input signal;   forming a second series of 24 frame/s progressive scan format frames from the first series of frames such that at least every other frame in the second series of frames is produced by motion compensated interpolation between a respective pair of successive frames of the first series of frames;   forming alternately odd and even fields from the second series of frames such that one field in every five is a repeat; and   forming said output 24 frame/s 60 field/s 3232 pulldown format digital video signal from the alternately odd and even fields formed from the second series of frames.   
     
     
       2. A method as claimed in claim 1, wherein alternate frames of the second series are produced by motion compensated interpolation equally between a respective successive pair of frames of the first series, and the remaining frames of the second series are not produced by motion interpolated compensation. 
     
     
       3. A method as claimed in claim 1, wherein the alternately odd and even fields are supplied at a rate of 5/2 times the rate of production of the frames in the second series of frames. 
     
     
       4. A method as claimed in claim 1, further comprising the step of storing the frames in the second series at the same rate as they are produced, and wherein the alternately odd and even fields are produced from the stored frames such that one field in every five is a repeat. 
     
     
       5. A method as claimed in claim 1, wherein each input field is repeated with a repeat rate 4R times, where R is a predetermined integer, a frame is produced in the first series for every 4R repeated input fields, a frame is produced in the second series for every 10R repeated input fields, and each frame in the second series is repeated with a repeat rate of 5R times.